The provided text offers excerpts from "The Arms Maker of Berlin" by Dan Fesperman, a novel that blends historical research with a fictional narrative. The story follows Nat, a historian drawn into a complex mystery after the suspicious death of his mentor, Gordon Wolfe. Nat's investigation leads him to uncover missing wartime intelligence documents related to Allen Dulles and the OSS, and he partners with Berta, a driven German researcher with her own family connections to the historical events. The narrative frequently shifts between Nat's present-day search and flashbacks to wartime Berlin, focusing on Kurt Bauer, a German arms manufacturer, and Liesl Folkerts, a member of the White Rose resistance group. As Nat uncovers the secrets within the "Fleece" report, he realizes the interconnectedness of these historical figures and the lasting impact of their actions and betrayals.